Once considered a key gauge of global economic activity, the Baltic Dry Shipping Index has withered to its lowest levels in 25 years. But the indicator has outlived its usefulness, investor Dennis Gartman said Wednesday. “I used to look to them as an indicator of economic activity. Now I look at them as an indicator ship owner stupidity,” publisher of the widely followed Gartman Letter said on “Fast Money.”

The index has long been used by market insiders to gauge demand for dry commodities.

But Gartman said that correlation no longer holds true.

A couple of years ago when the Baltic index approached 11,000, “every ship owner in the world build new ships,” scrapping small ships for “monstrous” ones, he said.

“It has nothing to do with the global economy now. It has everything to do with bad banking and stupid ship owners.”